A solid-liquid separator of the above-described system in which a screw does not come into contact with movable members and fixed members (solid-liquid separator of a contactless system) is well known as one of solid-liquid separators suitable for separating a liquid from an object to be treated, for example, organic sludge such as soybean wastes, wastewater from food processing, sewage drainage, and wastewater discharged from hog farms, sludge obtained by decomposition of the aforementioned organic sludge with microorganisms, inorganic sludge such as waste liquid from plating, ink waste liquid, pigment waste liquid, and paint waste liquid, and also vegetable wastes, fruit peelings, food residues, and tofu refuse.
JP-S59-218298-A discloses a screw-press dewatering apparatus in which a plurality of sliding plates disposed between fixed plates are integrally connected to each other, and a screw passes through holes in the fixed plates and the sliding plates.
WO00/32292 A1 (page 5) describes a configuration in which a screw passes through an inner circumferential contour of a filtration tube in which fixed plates and movable plates are arranged alternately with mutual superposition, opening edges of the fixed plates form the inner circumferential contour, and the movable plates oscillate in a range in which the opening edges do not penetrate into the inner circumferential contour in the fixed plates.
JP-2000-135595-A discloses a screw press device in which a screw passes inside a cylindrical space defined by the inner circumferential surface of a filtration tube having a large number of annular fixed plates arranged successively with gaps therebetween and a large number of annular movable plates arranged in corresponding gaps.
Other examples of patent documents disclosing solid-liquid separators of a contactless system include JP-2005-230852-A, JP-4036383-B2, and JP-4374396-B1.